The function that simulates PCR requires primersearch from the EMBOSS tool kit to be installed. This is not an R package, so it is not automatically installed. Type ?primersearch after installing and loading metacoder for installation instructions. Many of these operations can be done using other packages like phyloseq, which also provides tools for diversity analysis. The main strength of metacoder is that its functions use the flexible data types defined by taxa, which has powerful parsing and subsetting abilities that take into account the hierarchical relationship between taxa and user-defined data. In general, metacoder and taxa are more of an abstracted tool kit, whereas phyloseq has more specialized functions for community diversity data, but they both can do similar things. I encourage you to try both to see which fits your needs and style best. You can also combine the two in a single analysis by converting between the two data types when needed.